I'm trying to find the best way of dynamically positioning the blue path. The important part is its position relative to b and c. I currently am using \path [line,blue] let \p1=(a.south), \p2=(c) in (h.south) |- +(2,-0.5) |- (\x2, \y1) -- (c.north); for the blue path, but it really doesn't give me much dynamic control.

I've thought about trying add a couple of let points and taking the middle of their x-values, but I can't seem to figure out how to do that. It would look something like: \path [line,blue] let \p1=(a.south), \p2=(c), \p3=(b.east), \p4=(c.west) in (h.south) -| +( AAA , -0.5) |- (\x2, \y1) -- (c.north); where AAA would be something like ($(\x3 !0.25! \x4)$) or (\x3 + \x4)*0.75 but that really seems like a kludgy way of doing it.

So, what's the best way to draw this path so that it will scale dynamically??